<!DOCTYPE html>
<html>
	<head>
		<meta charset="UTF-8">
		<title></title>
	</head>
	<body>
		<input type="button" id="b" value="la" onclick="aa()"/>
		<input style="display: none;" type="button" id="a" value="lala" />
	</body>
	<script type="text/javascript">
		function aa(){
			document.getElementById("a").style.display="block";
		}	
	</script>
</html>
